ALTER TABLE `vn`.`workerLog` 
ADD COLUMN `changedModel` VARCHAR(45) NULL DEFAULT NULL AFTER `description`,
ADD COLUMN `oldInstance` TEXT NULL DEFAULT NULL AFTER `changedModel`,
ADD COLUMN `newInstance` TEXT NULL DEFAULT NULL AFTER `oldInstance`,
ADD COLUMN `changedModelId` INT(11) NULL DEFAULT NULL AFTER `newInstance`,
ADD COLUMN `changedModelValue` VARCHAR(45) NULL DEFAULT NULL AFTER `changedModelId`;